The technical field of the present invention is directed to mobile cellular networks, in particular to improving of quality of service provided by base stations to mobile units, which access the base stations of the mobile cellular network by means of a wireless link. For instance, the method and the base station of the present invention are applicable to WiMAX (WiMAX=Worldwide Interoperability for Microwave Access), 3GPP LTE (3GPP LTE=3rd Generation Partnership Project Long Term Evolution) and systems beyond 3G (3G=3rd Generation).
A general problem of mobile cellular networks is signal quality which can be described in the signal-to-interference-plus-noise ratio (SINR). A typical mobile cellular network is divided into a plurality of cells controlled by means of base stations comprising antenna units. Base stations can handle a plurality of communications at the same time. Nowadays, the amount of mobile communication is increasing rapidly. Thus, bandwidth problems may arise due to interference problems originating from a limited frequency band available for communicating in the mobile cellular network. Beam antennas beamforming based on multiple antennas can be used to optimize radio communication between a mobile unit and a base station. However, if two mobile units are located close to each other and communicate with similar radio frequencies, spatial interference is unavoidable.